1. Field of the Invention
This invention relates to a signal transfer circuit, and more particularly to a circuit for transferring an FM discriminator output to an amplifier, an FM multiplex demodulator or the like in the rear stage of an FM receiver.
2. Description of the Prior Art
In an existing FM radio receiver or AM-FM stereo radio receiver formed in an integrated circuit (IC), an FM demodulator circuit and a stereo demodulator circuit are formed in different respective momolithic IC chips, such as, monolithic middle-scale IC chips. In such case, the FM demodulator circuit produces a DC voltage comprised of a constant DC voltage and an S-curve DC voltage, and a composite stereo signal, such as, a pilot tone system FM stereo signal. However, in order to transfer only the composite stereo signal to the stereo demodulator circuit, a capacitor is externally connected between both IC chips and two external terminals are thus required solely for use in connecting such capacitor. Further, by reason of the foregoing, a biasing DC voltage produced in the FM demodulator circuit cannot be transmitted to the stereo demodulator circuit and, hence, a separated biasing DC voltage must be produced in the IC chip where the stereo demodulator circuit is formed.